Metal sacrificial-layer-assisted transfer is a promising strategy for transferring thermally annealed thin films onto flexible polymer substrates without exposing the receiver substrate to thermal damage. However, stable release of the annealed thin-film stack remains challenging because high-temperature annealing can alter the etching behavior of the sacrificial metal layer and the protective oxide layer. In this study, we propose a thin-film transfer process using a Ni metal sacrificial layer and etch access holes, in which an SU-8/Ti/SiO₂ transferable stack was fabricated on a rigid sapphire donor substrate, annealed at 400–700°C, selectively released by Ni etching, and transferred onto a flexible PET receiver substrate. As the annealing temperature increased from 400 to 700°C, the SiO₂ etch rate decreased from 6.8–6.96 to 2.61–3.83 nm/s, while the Ni release time increased from 72–77 to 82–95 min; nevertheless, the transferable stack was successfully transferred under all process conditions with image-based transfer yields of 58.81–82.76%, with the highest yield obtained for the 200 nm Ni sacrificial layer annealed at 550°C. These results demonstrate the process feasibility of the proposed metal sacrificial-layer and etch-access-hole-based transfer approach for transferring thermally annealed thin-film structures from rigid donor substrates to flexible receiver substrates.

Two-dimensional van der Waals (2D vdW) magnets have attracted enormous attention as an emerging material platform for magnetism, spintronics, and multifunctional applications. Their single-crystalline layered structures, layer-number controllability, and unique 2D properties provide unique opportunities that are difficult to achieve in conventional magnetic materials. However, the discovery and development of new 2D magnetic compounds require considerable time and effort, and only a limited number of these materials have been reported to be suitable for practical use. Therefore, materials engineering based on already established 2D vdW magnets has become an important research direction to explore new characteristics and find a practical route for device applications. This review summarizes recent materials engineering pathways for 2D vdW magnets. The main contents focus on the engineering strategy through electrostatic, chemical, lattice, symmetry, and heterostructure ways. These approaches provide practical design routes for tailoring magnetic properties beyond intrinsic 2D vdW magnets. Further progress will require broader application to various types of materials and delicate optimization that connects expanding fundamental magnetism with electromagnetic device applications.

Lead-free (Bi_1/2Na_1/2)TiO₃ (BNT)-based incipient piezoelectrics are highly promising for high strain actuators, but the high electric fields (4 ~ 6 kV/mm) required for activation limit practical device integration. In the current literature, large strains are frequently attributed to local structural variations like microscopic core-shell architectures. This work systematically investigates an alternative pathway by introducing A-site Strontium (Sr) excess non-stoichiometry into 0.74(Bi_1/2Na_1/2)TiO₃‒0.26SrTiO₃ (BNST26) ceramics. Microstructural and X-ray diffraction analyses reveal highly dense, uniform matrices completely devoid of micro-scale core-shell boundaries or macroscopic symmetry distortions, revealing that Sr non-stoichiometry diverges from typical Bi-excess mechanisms. Interestingly, despite negligible variations in overall macro-scale strain behavior across the composition series, a peak normalized strain (S_max/E_max) of approximately 804 pm/V is achieved at a low driving field of 2 kV/mm for the 1 mol% Sr-excess specimen (x = 0.010). These results indicate that while Sr non-stoichiometry weakly influences nanoscale stability, it can be inferred that subtle modifications of local defect configurations optimize switching energy barriers, enabling high-strain, low-drive-field performance in lead-free relaxors.

Ocean waves are not only a sustainable renewable energy source but also provide valuable information for monitoring marine environments and natural hazards. In this study, we developed a CNT/SEBS-based self-powered marine monitoring sensor utilizing a mechano-electrochemical mechanism, enabling simultaneous ultralow-frequency wave sensing and electrical energy harvesting. The developed sensor generated an open-circuit voltage of up to 60 mV and a short-circuit current of 80 μA/cm² without an external power source by exploiting variations in electrical double-layer capacitance induced by changes in the electrode–electrolyte interface. The capacitance increased from 0.1 μF to 2.4 μF with increasing immersion area, demonstrating the effectiveness of the proposed sensing mechanism. Furthermore, the CNT/SEBS bilayer exhibited high electrical conductivity together with excellent stretchability and flexibility, maintaining stable electrical responses under repeated water-level fluctuations. The proposed mechano-electrochemical self-powered sensor provides a promising platform for next-generation autonomous marine monitoring systems and sustainable blue-energy harvesting technologies.

As technologies such as artificial intelligence, autonomous driving, the Internet of Things, wearable electronics, and edge computing continue to spread in the era of the Fourth Industrial Revolution, the importance of hardware security for the safe storage, transmission, and processing of large volumes of data has grown substantially. One of the key components of such security systems is the true random number generator (TRNG), which produces unpredictable random numbers for cryptographic use. In recent years, research on TRNGs has increasingly moved beyond conventional CMOS-based approaches toward semiconductor devices built from emerging materials. These material-based TRNGs offer several advantages, including high integration density, low power consumption, compact form factors, and strong suitability for next-generation edge and IoT environments, because they can directly exploit the intrinsic stochasticity of the device itself as an entropy source. In this review, recent studies on TRNGs based on emerging material-based semiconductor devices are examined from the perspectives of entropy sources, device structures, randomness validation, and wearable/flexible extensions. By bringing together the key physical mechanisms, device platforms, evaluation criteria, and prospects for wearable and flexible electronics in edge and IoT environments, this review aims to provide a useful framework for future research on hardware security devices.

Wearable temperature sensors are becoming increasingly important for continuous health monitoring, personalized healthcare, and biointegrated electronic systems. However, conventional temperature-sensing platforms often suffer from limited thermal sensitivity, insufficient mechanical compliance, and unstable performance under repeated deformation, making it difficult to detect subtle physiological temperature variations in real time. Here, this tutorial status report presents a fabrication strategy for highly sensitive wearable temperature sensors based on gold-doped crystalline silicon nanomembranes. Gold diffusion into crystalline silicon introduces deep-level impurity states that modulate the Fermi level and shift the freeze-out region toward the physiological temperature range, enabling an ultrahigh negative temperature coefficient of resistance. By integrating the gold-doped silicon nanomembrane with a polyimide-supported ultrathin platform, neutral mechanical plane design, and serpentine mesh interconnects, the resulting device can provide high thermal sensitivity, fast response, conformal skin attachment, and stable operation under mechanical deformation. This fabrication approach is expected to broaden the use of impurity-engineered silicon nanomembranes in next-generation wearable sensors, flexible bioelectronics, and multifunctional healthcare monitoring systems.

With the rapid expansion of electric vehicles (EVs) and energy storage systems (ESS), ensuring the operational safety of lithium-ion batteries has become a critical technical challenge. Conventional battery management systems (BMS) primarily rely on threshold-based rule logic, which is limited in detecting coupled anomalies and early-stage degradation patterns. In this study, a deep learning-based framework for multivariate anomaly detection is proposed using BMS sensor data, including voltage, current, temperature, state of charge (SOC), and state of health (SOH). Five representative fault scenarios were defined, including thermal runaway precursors, cell voltage imbalance, SOC inconsistency, internal resistance increase, and communication delay. The proposed CNN-LSTM model was compared with conventional Rule-based methods and machine learning models, including Isolation Forest, Autoencoder, and LSTM. Experimental results show that the proposed model achieved the highest performance, with an F1-score of 0.885, an AUC of 0.94, and a detection delay of 8.1 s. In contrast, the Rule-based method exhibited a significantly higher false negative rate of 42.0%, indicating limitations in detecting complex anomaly patterns. These results demonstrate that the proposed spatiotemporal deep learning approach can significantly improve the accuracy and responsiveness of battery anomaly detection. Furthermore, the proposed method is expected to contribute to enhancing safety, reliability, and predictive diagnostics in next-generation intelligent BMS platforms.

Organic solar cells based on bulk heterojunction (BHJ) structures have attracted considerable attention because of their low fabrication cost, mechanical flexibility, and compatibility with solution-processing techniques. In BHJ organic photovoltaic devices, nanoscale morphology and crystallinity of the photoactive layer critically influence photovoltaic performance. In this study, the effects of solvent selection and thermal annealing on crystallization evolution and photovoltaic characteristics of P3HT:PCBM organic solar cells were systematically investigated. Three different solvents, including toluene, chlorobenzene (CB), and dichlorobenzene (DCB), were employed for active-layer fabrication, followed by post-thermal annealing treatment. UV–visible absorption spectroscopy revealed solvent-dependent differences in molecular ordering and intermolecular π–π interactions within the active layer. X-ray diffraction analysis confirmed that thermal annealing significantly enhanced crystallinity and lamellar ordering of P3HT domains, particularly for CB-processed films. Electrical characterization demonstrated that solvent evaporation behavior strongly affects photovoltaic performance. Among the investigated devices, the thermally annealed CB-processed device exhibited the highest power conversion efficiency of 1.83% with an enhanced short-circuit current density of 7.057 mA cm⁻². The improved device performance is attributed to optimized crystallization behavior and balanced nanoscale phase separation induced by the moderate evaporation characteristics of CB. In contrast, although DCB-assisted films exhibited relatively strong optical absorption and enhanced crystallinity, excessively slow solvent evaporation likely induced excessive aggregation and coarse phase separation, limiting efficient photovoltaic characteristics. These results demonstrate that solvent engineering combined with thermal annealing is an effective strategy for controlling morphology evolution and crystallization behavior in P3HT:PCBM bulk heterojunction solar cells.

This paper proposes a circular sequential lighting control method to reduce current imbalance and luminance deviation among multiple LED modules in AC-powered LED lighting systems. Conventional fixed-sequence lighting control repeatedly prioritizes the same LED modules in every rectified voltage cycle, which leads to unequal current distribution, luminance non-uniformity, and the accelerated degradation of specific modules during long-term operation. To address these limitations, a circular sequential lighting strategy is introduced, in which the lighting order is cyclically rotated at every rectified cycle, ensuring that all LED modules experience equal lighting opportunities. A prototype AC-LED lighting system consisting of four series-connected LED modules was implemented and experimentally evaluated. The results demonstrate that, while the conventional fixed-sequence method produces a maximum average current deviation of up to 1.6 mA among modules, the proposed method equalizes the average current across all modules to approximately 17.1 mA. Furthermore, the flicker index remains at 0.13, which is comparable to that of the conventional method, indicating that luminance uniformity is improved without degradation of optical performance. The proposed circular sequential lighting control effectively distributes electrical stress, enhances luminance uniformity, and improves long-term reliability, making it a practical and efficient solution for high-quality AC-LED lighting applications.

Metamaterials, as artificially engineered structures with unconventional mechanical and acoustic properties, have recently emerged as a transformative platform for enhancing the capabilities of triboelectric nanogenerator (TENG) systems. Since the invention of TENG devices, extensive efforts have been devoted to improving charge density, output stability, and overall performance. Conventional performance optimization strategies mainly rely on device-level improvements such as surface chemistry modification, microstructuring, and nanopatterning. However, limited emphasis has been given to system-level development of smart self-powered intelligent systems. The integration of metamaterials into TENG devices opens a new era by enabling frequency-selective localization, mechanical impedance matching, and controllable deformation pathways. These engineered mechanical structures not only improve energy harvesting efficiency but also introduce new functionalities into the system. This review systematically summarizes recent advances in metamaterial-integrated TENG systems across four major application domains: (i) energy harvesting, (ii) acoustic telecommunication and acoustic-to-electric conversion, (iii) self-powered sensing, and (iv) vibration suppression and monitoring. Overall, the integration of metamaterials into TENG systems will pave the way for next-generation sustainable, intelligent, self-powered devices with diverse functionalities.

Citations

• Fabrication and performance of integrated self-powered PAAM hydrogel flexible pressure sensors
  Huaikuan Zang, Chao Hu, Pan Niu, Yong Zhang
  Materials Science in Semiconductor Processing.2026; 214: 110899.     CrossRef
• Highly Stretchable Multiphase Composite Piezoelectret With Large Longitudinal and Transverse Piezoelectric Sensitivity for Self-Powered Electromechanical Sensors
  Yanfeng Lyu, Tiantian Gao, Jian Li, Zheng Hu, Xunlin Qiu, Yanxun Xiang, Fu-Zhen Xuan, Wee Chen Gan, Dietmar Auhl
  IEEE Sensors Journal.2026; 26(18): 27090.     CrossRef

Neuromorphic computing, which mimics the energy-efficient parallel processing capabilities of the human brain, has emerged as an alternative to traditional von Neumann architectures that struggle with high power consumption in the era of artificial intelligence (AI). Despite the potential of Si-based neuromorphic chips, they often face fundamental limitations in integration density and biological compatibility, necessitating the development of next-generation devices that can better emulate the ionic signaling of biological systems. This review provides a comprehensive analysis of the recent research trends in artificial synapses and neurons based on organic electrochemical transistors (OECTs), highlighting their unique ability to achieve high transconductance and mixed ionic-electronic conduction at ultra-low operating voltages. We discuss how OECTs successfully replicate diverse synaptic plasticities and complex neuronal spiking behaviors through advanced material engineering and structural optimizations such as vertical architectures. Furthermore, this review discusses the implementation of high-order neural functions, including associative learning and logic operations, which are facilitated by the inherent electrochemical dynamics of organic semiconductors. Finally, overcoming current challenges in reliability and scalability will establish OECTs as a pivotal platform for low-power neuromorphic hardware and bio-integrated electronics.

Citations

• Analysis of Yield and Electrical Characteristics of Ag Electrode-Based Volatile Threshold Switching Memristors with Al2O3 Dielectric Films Under Different ALD Process Conditions
  Wan-Sik Woo, Seung-Jin Lee, Moon-Seok Kim, Seung-Bae Jeon
  Journal of Electrical and Electronic Materials.2026; 39(5): 493.     CrossRef

This review introduces Corning’s Ribbon Ceramic process and the broader idea of ribbon ceramics―continuous, ultra-thin ceramic sheets made by tape or slot-die casting and fast, continuous sintering―covering key materials such as Al₂O₃, YSZ/ScSZ, PZT, LLZO, and LCO. Motivated by the need for scalable, energy-efficient ceramic components for electrification (green-hydrogen SOECs), next-generation Li-metal batteries, and compact piezo devices, we summarize capabilities and use cases using only publicly available information. Our main contribution is a clear platform view: continuous roll-to-roll conveyance with minutes-scale firing produces fully dense, fine-grained, high-purity ceramics at ~10-100 μm thickness with smooth native surfaces and controlled shapes, delivered as long rolls (up to ~300 ft), panels (~100 mm wide), or narrow strips (~0.5 mm). Illustrative results include 20-40 μm 3YSZ electrolytes for SOECs (high oxygen-ion conductance, ~1 GPa bend strength), LLZO garnet separators that cycle at 25℃ with interlayers, and free-standing LCO cathode ribbons tunable from dense to ~30% porous. For piezo acoustics, 60-80 μm PZT sheets (d33 ~300 pC/N) enable fine metallization and on-screen speakers, while fast firing reduces volatile loss and yields smaller grains. Together, these advances point to high-volume, lower-footprint manufacturing and faster adoption of novel ceramic membranes and substrates in SOEC/green-hydrogen systems, solid-state or hybrid lithium batteries, RF/power electronics, and piezo applications.

This review systematically examines the structural characteristics, compositional design strategies, and recent research trends of layered double hydroxides (LDHs), which are recognized as promising electrocatalyst materials in electrochemical nitrate-to-ammonia conversion. Despite the rapid growth in related research, achieving simultaneous high selectivity and efficiency remains a significant technical challenge due to the complex mechanisms of the nitrate reduction reaction (NitRR) and its inherent competition with the hydrogen evolution reaction (HER). In this study, we analyzed the structural contributions of LDH catalysts for maximizing nitrate reduction efficiency and systematically established key catalyst design indicators required to ensure optimal performance. Specifically, we provide a detailed investigation of the physicochemical mechanisms for enhancing NH₃ production by precisely regulating the adsorption energies of reaction intermediates and maximizing charge transfer efficiency through compositional control and defect engineering. Furthermore, we discuss advanced structural design strategies, such as core-shell tandem structures, MOF-derived architectures, and interlayer anion control, as effective methods for enhancing catalytic performance and optimizing mass transport processes. These insights offer a strategic roadmap for designing high-performance LDH catalysts and represent a critical step toward the practical implementation of sustainable green ammonia production systems, particularly for integration into high-efficiency membrane electrode assembly (MEA) technologies.

Cellulose nanofiber (CNF) has attracted significant attention as a next-generation insulating material due to its ecofriendly nature and outstanding functionalities. However, conventional kraft insulation paper suffers from limited dielectric breakdown strength and long-term reliability under high-voltage conditions, highlighting the need for alternative materials. In this study, kraft pulp was combined with five types of CNFs (A, B, C: wood-based / D, E: non-wood-based) to fabricate composite insulation papers, and their electrical and mechanical properties were systematically evaluated. The results showed that CNF incorporation generally enhanced density and tensile strength, while certain types contributed to lowering dielectric constant and improving breakdown strength. Among the wood-based CNFs, type C exhibited the most balanced performance in terms of dielectric stability and mechanical reinforcement. Among the non-wood-based CNFs, type E demonstrated notable improvements in structural compactness and tensile strength, suggesting favorable reliability. Therefore, this study identifies CNF C among wood-based types and CNF E among non-wood-based types as the most promising candidates for insulation performance enhancement, suggesting their applicability as next-generation insulating materials for power equipment and ecofriendly electronic devices.

Flexible and wearable electronics, which require stable operation under mechanical deformation, are increasingly utilizing Eutectic Gallium-Indium (EGaIn) for their conductive components. This study presents a systematic approach to fabricating highly reliable, deformable electrodes via a direct-ink-writing (DIW) 3D printing process using EGaIn as the functional ink. We conducted a thorough optimization of key printing parameters, specifically the extrusion pressure and printing speed, to achieve stable and uniform conductive lines. Through this optimization, we successfully established an optimal process window, achieving a stable line width of approximately 130 μm at an extrusion pressure of 300 kPa and a printing speed of 16 mm/s. The fabricated flexible electrodes exhibited exceptional electromechanical stability, maintaining negligible resistance change (< 0.82%) both under severe bending (3 mm radius) and after 100 repetitive bending cycles. This work demonstrates that the 3D printing of EGaIn is a viable and effective method for creating robust, high-performance electrodes for the next generation of deformable and wearable electronic devices.

Organic photovoltaics (OPVs) are attractive candidates for sustainable energy conversion due to their flexibility, lowcost processing, and compatibility with large-area fabrication. However, their efficiency is hindered by interfacial defects and vertical phase separation in the active layer, which induce charge imbalance and recombination losses. This work presents an interfacial engineering approach to overcome these limitations in P3HT:PC₇₀BM-based OPVs. Two key strategies were employed: (i) reducing the post-deposition annealing time of the active layer to suppress PC₇₀BM accumulation at the bottom electrode, and (ii) using a DCB:DCM mixed solvent system to regulate solvent evaporation, thereby promoting uniform film formation during PC₇₀BM overlay deposition. Devices fabricated with these optimizations exhibited notable enhancements, achieving short-circuit current density up to 15.83 mA/cm² and a 58.1% increase in power conversion efficiency compared to control devices. X-ray photoelectron spectroscopy confirmed reduced surface aggregation of PC₇₀BM, while X-ray diffraction indicated improved P3HT crystallinity and molecular ordering. These results highlight the critical role of interfacial and morphological control in enhancing charge separation and transport, offering a practical route toward efficient, reproducible, and stable OPVs.

The continuous rise of atmospheric carbon dioxide (CO₂) emissions highlights the urgent need for sustainable air purification technologies. Current Direct Air Capture (DAC) filters often rely on toxic amines, which limit long-term stability and safe application. Here, we report a non-toxic PAN-based nanofiber air filter fabricated by electrospinning and urea-assisted carbonization. Structural analyses confirmed the introduction of nitrogen functionalities that enhanced CO₂ affinity, while SEM and FT-IR revealed graphitic carbon formation. In air-chamber tests, the optimized carbonized nanofiber reduced CO₂ concentration from 25,000 ppm to 2,000 ppm, a level generally regarded as acceptable for indoor environments, while simultaneously removing over 95% of PM₁₀, PM_2.5, and PM_0.1 particulates. This dual functionality, combined with facile fabrication and material safety, demonstrates strong potential for PAN-derived carbon nanofiber membranes in DAC systems and eco-friendly air purification devices. These findings suggest a viable pathway toward scalable, sustainable air-filter technologies for carbon-neutral applications.

Humidity monitoring of exhaled breath has emerged as a vital approach for noninvasive respiratory health assessment, underscoring the need for sensitive and reliable humidity sensors. Despite its high conductivity and hydrophilic functional groups, reduced graphene oxide (rGO) often undergoes irreversible moisture adsorption and gradual oxidation by residual water, resulting in sensitivity degradation and long-term instability during cycling. In this study, a montmorillonite/reduced graphene oxide (MMT/rGO) composite is developed as a room-temperature humidity-sensing material, exhibiting an optimized response of 115%, more than 14 times higher than that of pristine rGO. This superior performance originates from the synergistic interaction between the reversible MMT swelling and the conductive rGO network near the electrical percolation transition, which ensures excellent stability and repeatability under repeated humidity cycles. These findings suggest that the MMT/rGO composite provides a cost-effective and biocompatible platform for next-generation wearable humidity sensors capable of continuous respiratory monitoring.

Abstract In this study, to develop composition ceramics for energy harvesting devices, Pb(Ni_1/3Nb_2/3)O₃-Pb(Zr Ti)O₃ system ceramics substituted with Pb(Mg_1/2W_1/2)O₃ were manufactured by conventional mixed oxide method using Li₂CO₃ and Na₂CO₃ (LNCO) as sintering aids. Their microstructure and piezoelectric properties were also investigated. At the specimen sintered at 930℃, high values of piezoelectric properties appeared: the dielectric constant (εr) of 2,522 planar electromechanical coupling factor kp of 0.602, and k₃₁ of 0.385, d31 = 229 [pC/N], g₃₁ = 10.13 [mV.m/N], Qm of 70, respectively. These values were suitable for the application of devices such as energy harvesting devices and ultrasonic devices.

Citations

• Optimization of the annealing process significantly enhances the breakdown field strength and energy storage performance of Pb0.92La0.08(Zr0.52Ti0.48)O3 thin films
  Dongchun Qiu, Jianing Zhu, Piyu Gong, Shibing Xiao, Huiting Sui, Huajun Sun
  Journal of Alloys and Compounds.2026; 1080: 190542.     CrossRef
• Low-Temperature Sintering and Piezoelectric Properties of the PZN-PZT Ceramics with LiBiO2
  Nayoon Kwon, Yong Geun Choi, Young Jin Lee, Dong Hun Yeo, Hyo Soon Shin, Joon-Hyung Lee
  Journal of Electrical and Electronic Materials.2026; 39(5): 501.     CrossRef

With the rapid development of digital technologies such as IoT, AI, and big data, electrical energy consumption is rapidly increasing. Electrical facilities that supply electrical energy are operated with high reliability and stability for end-of-life time. In addition, depending on the type of electrical load that consumes electrical energy in various forms, electrical insulation systems deteriorate due to electrical and thermal stress, which reduces electrical and mechanical insulation strength. Due to such continuous stress and electrical transient phenomena, electrical facilities may experience electrical accidents due to electrical insulation breakdown before the expected design lifetime. In addition, periodic inspections according to related regulations must be conducted to prevent unexpected electrical accidents, but this leads to problems in which the electrical facilities cannot be turned off. Therefore, it is believed that an uninterruptible diagnostic judgment technique that determines compliance with related regulations such as electrical facility technology standards, internal wiring regulations, and inspection regulations without turning off the electrical facilities and at the same time detects abnormal conditions of the facilities early, it is possible to prevent electrical accidents and improve the efficiency of electrical facilities. In this paper, we propose an uninterruptible power diagnosis judgment technique that can prevent or reduce electrical accidents in cast-iron transformers by applying judgment criteria of diagnostic sensors for various types of measurement parameters that can diagnose and evaluate the presence or absence of abnormalities in electrical equipment, including partial discharge, and AI algorithms learned from data of diagnostic sensors.

The mounting demand for sustainable, self-powered biomedical devices, particularly those engineered for extreme environments, has established triboelectric nanogenerators (TENGs) as a prominent technology in energy harvesting research. This review examines state-of-the-art biomaterial synthesis strategies essential for developing high-performance bioelectronic TENGs that can operate reliably under harsh conditions, including elevated temperatures, extreme humidity, and mechanical strain. It begins with a comprehensive overview of the fundamental principles of triboelectricity and subsequently addresses the pivotal challenges associated with efficient charge generation and retention in such challenging settings. The content places particular emphasis on recent advancements in composite material engineering and structure design for high-efficiency mechanisms, with a particular focus on biocompatible and environmentally resilient materials. The integration of TENGs into wearable sensors, implantable devices, and self-powered monitoring systems is also investigated, demonstrating their transformative potential for bioelectronic applications. Our goal subsequently underscores persistent limitations to overcome, including those pertaining to fabrication scalability and long-term operational stability, while concurrently proposing prospective research directions. Consequently, this work underscores how innovative biomaterial synthesis and bioelectronic devices can enable the development of next-generation, high-performance, self-powered devices suited for extreme biomedical environments.

This study investigates the insulation performance of a 66 kV dry-type submarine cable used in offshore wind farms under mechanical aging. During installation and operation, submarine cables are subjected to various mechanical stresses, including tension, compression, and bending, which can lead to insulation deterioration. In this study, XLPE samples extracted from a submarine cable were prepared and subjected to controlled tensile strain below the yield strain to evaluate their mechanical and electrical performance. Changes in tensile strength, elongation, and tan δ (dielectric loss factor) were measured to assess the extent of aging. The results indicate that as the applied strain and exposure duration increased, tensile strength and elongation decreased, while tan δ values increased, signifying a decline in electrical insulation performance. A strong negative correlation (R = -0.809) was observed between tan δ and tensile strength, demonstrating that mechanical aging significantly affects electrical properties. These findings highlight the importance of minimizing excessive mechanical stress during the installation and operation of submarine cables. The results provide valuable insights for enhancing the reliability of submarine cables in offshore wind farms and emphasize the necessity of optimized design and maintenance strategies to mitigate the effects of mechanical aging.

The increasing demand for renewable energy is driving the rapid expansion of the offshore wind industry, leading to intensified research on subsea cables. These cables endure combined thermal, electrical, and mechanical stresses, with mechanical stress being a critical failure factor. Environmental changes, such as seabed scouring, free spans, and seismic activity, accelerate cable degradation by introducing additional dynamic loads. Conventional monitoring systems primarily track thermal stress, lacking the ability to assess mechanical impacts. This study develops a system to simultaneously measure thermal and mechanical stress in subsea cables. Laboratory experiments confirm the system’s reliability, showing a temperature measurement error within 0.8% at 60℃ and a strain measurement error within 13% at 378 με. The proposed system aims to enhance failure prediction and maintenance strategies for offshore wind subsea cables.

This study aimed to elucidate factors limiting power conversion efficiency (PCE) in GaN-based micro-light-emitting diodes (μ-LEDs). To this end, we investigated the effects of operating temperature and chip-size of μ-LEDs on their efficiency. For the investigation, 460 nm-emitting μ-LEDs with various chip-sizes were fabricated; then their characteristics were carefully measured from 100 to 400 K. As the chip-size decreases and the operating temperature increases, their PCE and external quantum efficiency (EQE) decrease, while voltage efficiency (VE) increases. This indicates that the EQE plays a more important role than the VE in determining the PCE of μ-LEDs. Particularly, for a chip-size of 20 × 20 μm², the EQE was very lower and the ideality factor was unexpectedly higher compared to the others for all operating temperatures, which is believed to be due to the critical plasma damage at the sidewall during dry-etching process for the chip-size < 20 × 20 μm².

Neuromorphic computing, inspired by the biological mechanisms of neural signal transmission, has emerged as a promising technology for efficient and parallel data processing with minimal power consumption. In this study, we developed floating-gate organic thin-film transistors (OTFTs) with self-assembled monolayer (SAM)-based tunneling layers to mimic the characteristics of artificial synapses. The tunneling layers were formed using mixed phosphonic acid SAMs with varying ratios of octadecylphosphonic acid (ODPA) and 12-pentafluorophenoxydodecylphosphonic acid (PFPA). The influence of these ratios on the memory and neuromorphic characteristics of the devices was systematically evaluated. Our results revealed that the ODPA ratio significantly impacts the hysteresis window, with higher ODPA content yielding improved memory characteristics. Conversely, the PFPA : ODPA ratio of 2:1 exhibited the lowest non-linearity (NL = 0.48), demonstrating the potential for highly accurate weight updates in neuromorphic devices. Additionally, pulse width modulation studies showed that a pulse width of 100 ms optimized the linearity and stability of long-term potentiation (LTP) and depression (LTD) characteristics. The combination of sol-gel processed AlOx as a floating-gate layer and tailored SAM-based tunneling layers allowed for precise control of device performance. These findings highlight the importance of molecular engineering in designing SAM layers to balance memory retention and neuromorphic functionality. This study provides a pathway for advancing organic floating-gate transistors as a core component in next-generation neuromorphic computing systems.

In parallel with the efforts to improve the device performance in modern integrated circuits, it is necessary to downscale their core components, field-effect transistors (FETs), generally gauged by their physical gate length. Upon such device scaling, the emergence of the short-channel effect impedes further scaling into the nanometer scale in the silicon VLSI (Very-Large-Scale-Integration) system. To address this issue, two-dimensional (2D) semiconductors, leveraging their atomically thin thickness and dangling-bond-free characteristics, are being highlighted as a material solution for future scaling technology without severe mobility degradation. Despite the expected ideal physical properties, 2D semiconductors have yet to realize their full potential owing to the limited development of integration technology. In this context, we survey and review the tailored van der Waals integration technologies for 2D FETs. In particular, we provide an in-depth study of both van der Waals integrated contact and dielectric methods along with an explanation of customized materials. In essence, this van der Waals integrationcentered approach will be a core strategy to implement the high-performance 2D transistors that meet the demand of FET miniaturization.

Citations

• Single-Molecule Manipulation Techniques Based on Mechanical, Electrical, and Structural Control
  Jeong Hun Shin, Tae Won Nam
  Journal of Electrical and Electronic Materials.2026; 39(3): 247.     CrossRef

This study examined the crystallinity and potential of BaTiO₃ powder, prepared by hydrothermal synthesis at 60 nm, as a dielectric material for automotive MLCCs under varying heat treatment temperatures. At temperatures above 850℃, the powder exhibited an orthorhombic structure, with crystallinity and particle size increasing as the temperature rose. In the range of 850~900℃, the powder displayed a uniform particle size distribution and minimal agglomeration, with particles ranging between 150~200 nm. Additionally, it was confirmed that the heat treatment temperature significantly impacts the properties of BaTiO₃ powder, which are critical for the dielectric performance required in X7R MLCCs used in automotive applications. Specifically, high-temperature treatment (above 850℃) was essential for enhancing the powder's crystallinity and forming a stable core-shell structure, which is crucial for achieving stable TCC (Temperature Coefficient of Capacitance) characteristics. It was confirmed that increased crystallinity at temperatures above 850℃ facilitated the development of the core-shell structure through interactions with additives, thereby achieving the necessary characteristics required for highly reliable automotive MLCCs.

Citations

• [100]-Oriented BaTiO₃ via reaction-mediated texturing with SrTiO₃ templates
  Nu-Ri Ko, Jinsung Chun, Kutak Lee, Chang Kyu Jeong, Wook Jo
  Journal of the Korean Ceramic Society.2026; 63(4): 574.     CrossRef
• Effect of BaZrO3 Addition on the Frequency and Temperature Dependent Dielectric Properties of BaTiO3-Based Ceramics
  Won-Su Lee, Jong Kyu Lee, Moon-Taek Cho, Jung Rag Yoon
  Journal of Electrical and Electronic Materials.2026; 39(5): 478.     CrossRef
• Enhanced dielectric performance in BaTiO3 ceramics by diffusion-controlled core-shell structuring with 2D Ca2Nb3O10 nanosheets
  Tae Yeong Song, Junwon Lee, Nayeon Kwon, Do-Kyun Kwon
  Journal of the Korean Ceramic Society.2026; 63(5): 1194.     CrossRef

The printed and bifacial organic photovoltaics (OPVs) using a semi-transparent electrode structure to enhance light management were investigated. To optimize energy-band alignment for bifacial device structure, a cathode interlayer of ZnO nanoparticles with a low work function of 3.9 eV combined with a polyethyleneimine (PEI) layer was employed. Photon distribution simulations revealed the influence of structural parameters on device conductivity, light absorption, and surface morphology. The dispensing strength, adjusted via applied voltage during printing, significantly impacted device performance. At 13 V and 17 V, J-V characteristics were consistent; however, at 20 V, line width increased by approximately 100%, resulting in a 50% reduction in PCE. These findings highlight the critical relationship between spraying strength, line width, and efficiency, offering valuable insights for advancing printed OPV technologies.

In this study, we proposed β-Ga₂O₃ JFET using nitrogen doping and analyzed the electrical characteristics. In β-Ga₂O₃, nitrogen ions act as a deep acceptor and are used to implement the current blocking layer. By using this characteristic of the nitrogen ion, in the proposed JFET, nitrogen ions are used to obtain gate control and pinch off the channel of the JFET. The numerical TCAD simulation was performed to design and analyze the proposed JFET. The simulated forward and reverse characteristics of the proposed JFET were obtained as a function of JFET width and nitrogen doping concentration. The maximum breakdown voltage of 1.7 kV was obtained with the on-resistance of 16.7 mΩ·cm² when the channel width was 1.5 μm and nitrogen doping concentration is 1×1018/cm³, respectively.

Smart electronic skin (E-skin) is an emerging technology that integrates electronic devices with human skin, enhancing human-machine interactions. One critical challenge in its development is effective thermal management to ensure device reliability, longevity, and user comfort. This review highlights passive cooling techniques - thermal conduction, convection, radiation, and phase-change materials - as key strategies to address this challenge without additional power consumption. These integrated mechanisms have demonstrated the ability to efficiently dissipate heat, preventing thermal buildup and maintaining optimal performance in E-skin devices. Recent advancements indicate that combining these methods can significantly enhance the thermal management of flexible electronics. Future research should focus on refining these materials and techniques to overcome challenges related to cost, durability, and environmental stability, thereby advancing the practical application of E-skin technology.

Citations

• Wearable sweat glucose monitoring patches enabled by double network hydrogel-MoS2/PEDOT: PSS nanocomposite
  Suraj Shinde, Omkar A. Patil, Sang Yoon Park, Se Jin Choi, Omkar Pawar, Daniel J. Joe, Sooman Lim, Han Eol Lee
  Microchemical Journal.2025; 215: 114309.     CrossRef